Send mail to: mgnet@cs.yale.edu for the digests or bakeoff mgnet-requests@cs.yale.edu for comments or help Anonymous ftp repository: www.mgnet.org (128.163.209.19) Current editor: Craig Douglas douglas-craig@cs.yale.edu WWW Sites: http://www.mgnet.org or http://casper.cs.yale.edu/mgnet/www/mgnet.html or http://www.cerfacs.fr/~douglas/mgnet.html or http://phase.hpcc.jp/mirrors/mgnet or http://www.tat.physik.uni-tuebingen.de/~mgnet Today's editor: Craig Douglas (douglas-craig@cs.yale.edu) Volume 11, Number 9 (approximately September 30, 2001) Today's topics: Open Position in Darmstadt (Computational Bioelectromagetics) 2 Open Positions at SMU Preprint: Preconditioning a Mixed Discont. FEM for Radiation Diffusion Preprint: An Unstructured Multigrid Method Based on Geometric Smoothness Preprint: Introduction to Robust Multigrid Technique Ph.D. Thesis: Stefan Reitzinger ETNA, Volume 12 Workshop on Current and Future Trends in Numerical PDE's, Feb. 8-9, 2002 UCLA MOV2001 Workshop: Dec. 3--5, 2001 Japanese Mirror's New URL Code Query ------------------------------------------------------- Date: Tue, 04 Sep 2001 12:58:03 +0200 From: Markus ClemensSubject: Open Position in Darmstadt (Computational Bioelectromagetics) The Computational Electromagnetics Laboratory (www.TEMF.de) at the Darmstadt University of Technology invites applications for an open Phd/Postdoc research position. The position involves a research project supported by the DFG (Deutsche Forschungsgemeinschaft) centered around the numerical simulation of current density distributions in high resolution 3D anatomy models of human bodies. Typical applications are the exposure to slowly-varying ambient electromagnetic fields of high intensity and their impact on pacemakers. The project involves the solution of very large systems of equations arising from real-valued stationary current formulations or complex-valued eddy current formulations, for which multigrid schemes have to be used in a distributed computational environment. The Computational Electromagnetics Laboratory is continuously focused on the development of methods and algorithms for the numerical simula- tion of electromagnetic fields and their application to real world technical problems. With its staff, consisting of about 30 researchers at phd- and postdoc-level and its state-of-the-art research facilities, it offers an excellent and creative environment for high-profile re- search in the field of Computational Electromagnetics. It is the origin of the so-called "Darmstadt School" of Computational Electromagnetics involving the Finite Integration Method, the canonical discretization method for Maxwell's Equations of electrodynamics. For this research project we are looking for outstanding university graduates with a specialization in Applied Mathematics/Scientific Compu- tation, Computational Engineering, Electrical Engineering, Computer Science or Physics. Programming skills and the ability to work in a team, as well as a strong interest in the field of scientific computing are an advantage for this position. Applications accompanied by the usual documents (curriculum vitae with date of birth, diplomas, list of publications, ...) should be send to Prof. Dr.-Ing. Thomas Weiland Dept. Electrical Engineering and Information Technology Laboratory for Computational Electromagnetics (TEMF) Schlossgartenstrasse 8 64289 Darmstadt, Germany Email: weiland@temf.tu-darmstadt.de URL: http://www.temf.de ------------------------------------------------------- Date: Fri, 28 Sep 2001 16:50:44 -0500 (CDT) From: zchen@post.cis.smu.edu (Zhangxin Chen) Subject: 2 Open Positions at SMU Southern Methodist University Dedman College Department of Mathematics Applications are invited for two positions at either the senior level (tenured) or junior level (tenure-track), to begin in the fall semester of 2002. Applicants must have a strong commitment to teaching at all levels and provide evidence of outstanding research. The Department of Mathematics has an active doctoral program in computational and applied mathematics with twelve of the fifteen present faculty conducting research in these areas. Current research includes numerical analysis of differential equations, dynamical systems, bifurcation theory, finite element methods, perturbation methods, and mathematical software with applications to areas such as nonlinear optics, lasers, solidification, vortex dynamics, reservoir simulation, pattern formation, and nonlinear waves. To apply, send a letter of application with a curriculum vitae, a list of publications, and a research and teaching statement to: The Faculty Search Committee, Department of Mathematics, Southern Methodist University, P.O. Box 750156, Dallas, Texas 75275-0156. Applicants must also arrange for three letters of recommendation to be forwarded to the Faculty Search Committee. The committee will begin its review of the applications on or about January 14, 2002. To ensure full consideration for the positions, the application must be postmarked on or before January 14, 2002, but the committee will continue to accept applications until the positions are filled. The committee will notify applicants of its employment decision after the positions are filled. SMU will not discriminate on the basis of race, color, religion, national origin, sex, age, disability or veteran status. SMU is also committed to nondiscrimination on the basis of sexual orientation. Visit the department's home page at http://www.smu.edu/math for more information. The Search Committee can be contacted by sending e-mail to mathsearch@mail.smu.edu. [Tel: (214) 768-2506; Fax: (214) 768-2355] ------------------------------------------------------- Date: Mon, 20 Aug 2001 12:50:40 -0400 (EDT) From: benzi@mathcs.emory.edu Subject: Preprint: Preconditioning a Mixed Discont. FEM for Radiation Diffusion Preconditioning a Mixed Discontinuous Finite Element Method for Radiation Diffusion James S. Warsa, Michele Benzi, Todd Wareing, and Jim Morel We propose a multilevel preconditioning strategy for the iterative solution of large sparse linear systems arising from a finite element discretization of the radiation diffusion equations. In particular, these equations are solved using a mixed finite element scheme in order to make the discretization discontinuous, which is imposed by the application in which the diffusion equation will be embedded. The essence of the preconditioner is to use a continuous discretization of the original, elliptic diffusion equation for preconditioning the discontinuous equations. We have found that this preconditioner is very effective and makes the iterative solution of the discontinuous diffusion equations practical for large problems. This approach should be applicable to discontinuous discretizations of other elliptic equations. We show how our preconditioner is developed and applied to radiation diffusion problems on unstructured, tetrahedral meshes and show numerical results that illustrate its effectiveness. Editor's Note: See http://www.mgnet.org/mgnet-papers.html ------------- or http://www.mathcs.emory.edu/~benzi/Web_papers/pubs.html ------------------------------------------------------- Date: Thu, 20 Sep 2001 10:06:35 -0700 (PDT) From: "Edmond Chow" Subject: Preprint: An Unstructured Multigrid Method Based on Geometric Smoothness An Unstructured Multigrid Method Based on Geometric Smoothness Edmond Chow Center for Applied Scientific Computing Lawrence Livermore National Laboratory L-560, Box 808, Livermore, CA 94551 echow@llnl.gov Abstract For non-M-matrices, this paper proposes an unstructured multigrid method that only attempts to interpolate in the directions of geometrical smoothness. These directions are determined by analyzing samples of algebraically smooth error, e. Neighboring grid points i and j are called smoothly coupled if e_i and e_j are consistently nearby in value. In addition, these differences may be used to define interpolation weights. These new ideas may be incorporated into the algebraic multigrid method. Test results show that the new method can have much lower grid and operator complexities compared to AMG, leading to lower solve timings. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. Editor's Note: See http://www.mgnet.org/mgnet-papers.html ------------- ------------------------------------------------------- Date: Thu, 30 Aug 2001 11:04:42 +0000 (GMT) From: "Serguei Martynenko (CIAM)" Subject: Preprint: Introduction to Robust Multigrid Technique Introduction to Robust Multigrid Technique Part A: Structured Grids S.I. Martynenko Central Institute of Aviation Motors Moscow, Russia martyn_s@mail.ru ABSTRACT Robust Multigrid Technique is intended to be a computational core of black box software for solving physically meaningful problems on structured grids. To overcome problem of robustness for a sufficiently large class of the partial differential equations, the technique consists of two parts: ``analytical'' part (adaption of the boundary volume problems to the technique) and ``computational'' part (control volume discretization and solution of discretized problems by original multigrid solver). Interpolation and pre-smoothing are eliminated from the ``computational'' part. In addition, the most powerful coarse grid correction strategy used in the technique makes task of the smoother the least demanding. Expanded robustness of the multigrid technique is a result of adaption of equations, extremely accurate formulation of the discrete problems on the coarse grids, original coarsening, the most powerful coarse grid correction strategy, construction of problem-independent transfer operators, and absence of pre-smoothing and interpolation. The preprint reports the essential principles of the robust multigrid technique (Chapter 1), application to handle model problems (Chapter 2), multigrid software (Chapter 3 and 4) and parallel implementation (Chapter 5). Editor's Note: See http://www.mgnet.org/mgnet-papers.html ------------- ------------------------------------------------------- Date: Tue, 02 Oct 2001 11:30:31 +0200 From: Reitzinger Stefan Subject: Ph.D. Theses My Ph.D. theses, "Algebraic Multigrid Methods for Large Scale Finite Element Equations," is available via the link http://www.trauner.at/book_detail.asp?artnr=20134361&id_titel=6131 Stefan Reitzinger http://www.sfb013.uni-linz.ac.at/~reitz/ * * * * * Alegbraic Multigrid Methods for Large Scale Finite Element Equations Stefan Reitzinger Abstract The numeral simulation of physical models is of great importance. Instead of performing experiments with a real life experimental setup, such an experiment can be done virtually by computer simulation. We use the finite element method, which in general produces a large sparse symmetric and positive definite system of linear equations. In particular we concentrate on the robust and efficient solution of the arising linear system of equations, which is one key task in the whole numerical simulation process of many applications appearing in science and engineering. The present work consists in the construction of an algebraic multigrid method for various kinds of problems. Such methods are of interest if a finite element code does not support a hierarchy of meshes, or if classical methods (direct or iterative linear equation solvers) require too much memory and/or computation time. In addition a parallel version of the algebraic mutigrid method is constructed. The proposed algorthms are implemented in the algebraic software package PEBBLES. Many numerical examples ae given in order to show the high efficiency and flexibility of the method. Schriftenreihe der Johannes-Kepler-Uni Linz, Reihe C, Bd. 36 1. Auflage 2001 134 Seiten, A5, broschiert, ISBN 3-85487-259-3 ArtNr. 20134361 ATS 255,00 EUR 18,50 Lektorat: ekindermann@trauner.at ------------------------------------------------------- Date: Thu, 13 Sep 2001 08:48:57 -0400 (EDT) From: Lothar Reichel Subject: ETNA, Volume 12 Table of Contents, Electronic Transactions on Numerical Analysis (ETNA), vol. 12, 2000. ETNA is available at http://etna.mcs.kent.edu and at several mirror sites, as well as on CDROM. Papers will be added to the volume until the end of this year as soon as they are accepted for publication. Presently the following papers have been published in volume 12: G. Meurant, Numerical experiments with algebraic multilevel preconditioners, pp. 1-65. H. Zhang, Numerical condition of polynomials in different forms, pp. 66-87. M. J. Castel, V. Migallo'n, and J. Penade's, On parallel two-stage methods for Hermitian positive definite matrices with applications to preconditioning, pp. 88-112. R. S. Varga, Gersgorin-type eigenvalue inclusion theorems and their sharpness, pp. 113-133. F. B. Belgacem and S. C. Brenner, Some nonstandard finite element estimates with applications to 3D Poisson and Signorini Problems, pp. 134-148. S. Ehrich and A. Rathfeld, Piecewise linear wavelet collocation, approximation of the boundary manifold, and quadrature, pp. 149-192. J.-B. Chen and M.-Z. Qin, Multi-symplectic Fourier pseudospectral method for the nonlinear Schrodinger equation, pp. 193-204. B. Fischer and F. Peherstorfer, Chebyshev approximation via polynomial mappings and the convergence behaviour of Krylov subspace methods, pp. 205-215. A. A. Dubrulle, Retooling the method of block conjugate gradients, pp. 216-233. ------------------------------ Date: Sun, 30 Sep 2001 10:23:00 -0400 (EDT) From: Craig Douglas Subject: Workshop on Current and Future Trends in Numerical PDE's, Feb. 8-9, 2002 CURRENT AND FUTURE TRENDS IN NUMERICAL PDE's: Where is the field, and where is it going? Friday and Saturday, Feb 8-9, 2002 Texas Institute for Computational and Applied Mathematics (TICAM) The University of Texas at Austin. Austin, Texas, USA URL: http://www.ticam.utexas.edu/~arbogast/jim.html The field of computational PDE's is undergoing several paradigm shifts due to the advent of powerful computers. - It has prompted the development of new types of algorithms, like domain decomposition methods for elliptic problems and the highly parallelizable discontinuous Galerkin methods for non-linear hyperbolic problems. - It has rendered the idea of strict approximation error control a plausible possibility. This has resulted in the development of new continuous dependence results for linear and non-linear PDEs based on which adaptive strategies are being devised to monitor and control the error. - It has also been a catalyst for the devising and application of numerical schemes based on multi-resolution analysis. - It has enhanced the range of physical phenomena that can be modeled by PDEs and then approximated. This is the case, for example, of models that take into account physical phenomena taking place in different scales and of models devised to capture stochastic mechanisms. The goal of the conference is to gather different communities working in computational PDEs and expose participants to some of the main current trends in the field. This meeting will challenge its participants to confront the many aspects of the task of approximating the solutions of mathematically sophisticated models, and it will expose them to some of the tools developed in the different sub-communities of computational PDE's. ------------------------------------------------------- Date: Thu, 20 Sep 2001 12:32:27 -0700 (PDT) From: "Joseph R. Shinnerl" Subject: UCLA MOV2001 Workshop: Dec. 3--5, 2001 The UCLA IPAM Workshop on Multilevel Optimization in VLSICAD has been rescheduled for Dec. 3-5, 2001. We again invite you to attend. Please visit http://www.ipam.ucla.edu/programs/mov2001/ for more information and online registration. -Joe Shinnerl and Jason Cong * * * * * Editor's Note: The talks scheduled include Achi Brandt (The Weizmann Institute of Science) Multiscale Optimization Strategies Jason Cong (UCLA CS) Computational Challenges in Gigascale VLSICAD Ding-zhu Du (University of Minnesota CS&E) Guillotine Cut in Approximation Algorithms Stephan Hartmann (TU Berlin) New Complexity Issues and Algorithms on Channel and Switchbox Routing Bruce Hendrickson (Sandia National Labs) A Survey of Multilevel Combinatorial Methods in Scientific Computing George Karypis (University of Minnesota CS&E) Multilevel Algorithms for Hypergraph Partitioning: Single and Multiple Constraints Michael Lewis (College of William & Mary, Mathematics) Levels of Resolution and the Optimization of Systems Governed by Differential Equations John Lillis (University of Illinois Chicago) Topics in Middle-Down Placement Stephen Nash (George Mason University, Systems Eng. & Op. Res.) Multigrid Algorithms for Discretized Optimization Problems Rob A. Rutenbar (Carnegie Mellon University) Hierarchical Synthesis for Industrial-Scale Analog Intellectual Property Majid Sarrafzadeh (UCLA CS) SPS Project: Strategically Reconfigurable Systems Lieven Vandenberghe (UCLA EE) Applications of Convex Optimization in Power and Ground Network Design and Wire Sizing Chandu Visweswariah (IBM Research) Optimization Challenges in Transistor Sizing Chris Walshaw (University of Greenwich, Computing and Math. Sci.) Multilevel Refinement for Combinatorial Optimisation Problems Jacob White (MIT EECS) Multiscale Algorithms for Electrical Peformance Analysis of Interconnect Gabriel Wittum (University of Iowa, Management Sciences) Filtering Algebraic Multigrid Martin D.F. Wong (University of Texas at Austin, CS) The Floorplan Design Problem ------------------------------------------------------- Date: Fri, 14 Sep 2001 23:59:54 +0900 (JST) From: NISHIDA Akira Subject: Japanese Mirror's New URL Thank you for your kind permission for mirroring your site. Due to the recent integration of national laboratories in Japan, the Electrotechnical Laboraty, where our site http://phase.etl.go.jp/ locates, has become a division of AIST, the National Institute of Advanced Industrial Science and Technology. We will appreciate if you could use the following URL as the new location of our mirror: http://phase.hpcc.jp/mirrors/mgnet/ Thank you very much for your cooperation. Yours faithfully, Akira Nishida -- NISHIDA Akira Department of Computer Science, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 JAPAN TEL +81-3-5841-4076 FAX +81-3-3818-1073 E-mail: nishida@is.s.u-tokyo.ac.jp ------------------------------------------------------- Date: Thu, 20 Sep 2001 13:14:18 +0900 (KST) From: "R. Ganesh" Subject: Code Query I am a research student at POSTECH korea. I am looking for a 2D xy Poisson solver (cartesian) which can handle circular boundary (say conducting). i.e., \partial^2 \varphi/\partial x^2 + y-part = f(x,y) with varphi=0 on a circular boundary x^2 + y^2 =R^2. in fact a uniform grid spaced xy solver would do. This is because I would like to avoid the 1/r problems faced in poisson solutions in regular cylindrical polar co-ordinates at origin. Do you have some suggestions as to availability of such code? with regards ganesh Editor's Note: If your code solves his problem, please send him email ------------- directly. R. Ganesh e-mail : ganu@kitty.postech.ac.kr Plasma Application Modeling Group. Phone : (Off) 82-54-279-8086 Department of Electrical Engineering. Fax : (Off) 82-54-279-2903 Pohang University of Science and Phone : (Home) 82-54-279-3963 Technology (POSTECH). San-31 Hyoja, Pohang 790-784, S. Korea. ------------------------------ End of MGNet Digest **************************